This invention relates to an improved steering keel for a snowmobile ski and more particularly to a steering keel which is constructed to enhance the steering characteristics of a snowmobile being propelled.
Snowmobile operators frequently encounter difficulty in negotiating turns when the snowmobile is traversing ice or hardened snow. The skiis, which are conventionally pivotally mounted at the front of a snowmobile to control the direction of snowmobile travel, frequently tend to slide over the ice and hardened snow and the turning radius is greatly increased. When snowmobiles are being raced, or otherwise traveling in groups, accidents frequently result when a snowmobile operator is unable to positively turn the snowmobile in a predetermined arc. Racers, who negotiate turns at extremely high velocities, are particularly concerned with predictable steering characteristics.
When the snowmobile skiis do not bite into the surface being traversed and a snowmobile slides through a turn, snowmobile operators frequently oversteer in the direction of the turn. When the turn is completed, the driver frequently encounters difficulty in regaining full and complete control of the snowmobile because the driver will sometimes oversteer in the opposite direction. The driver must continue to adjust the steering until full control is resumed.
It has been found that if the snowmobile keel obtains good bite into the surface being traversed, the snowmobile racer need not turn the skiis as much in the direction of the turn to negotiate a curve. This minimizes the "backlash" effect and provides much more positive and reliable steering.
One way to obtain increased bite is to add weight to the front of the snowmobile for the purpose of increasing the downward force exerted on the skiis in an attempt to force the steering keels mounted on the undersides of the skiis into biting engagement with the ice. This has the disadvantage of increasing the drag on the forward skiis and racing speed on the straight away portion of the race track is accordingly reduced.
With apparatus constructed according to the present invention, weight may be rearwardly shifted from the front to the rear of the snowmobile. This has the attendant advantage of increasing the downward force exerted on the snowmobile drive track, which is conventionally mounted at the rear of the snowmobile, and thus the traction of the drive track is increased. Slippage of the track is thereby reduced and the track studs better penetrate the ice and thus the forward propelling characteristics of the track is enhanced. Another attendant advantage of rearwardly shifting the weight from the forwardly disposed steering skiis to the endless drive track is that the power required to overcome the frictional forces between the front steerable skiis and the surface being traversed is reduced and thus not as much power is required to forwardly propel the snowmobile.
Accordingly, it is an object of the present invention to provide a snowmobile ski which will provide positive steering capabilities.
It is another object of the present invention to provide a snowmobile ski which will enhance the reliability of a snowmobile turning in a predictable arc even though ice is being traversed.
It is another object of the present invention to provide a keel for a snowmobile ski which will enhance the bite into the surface being traversed.
It is another object of the present invention to provide a snowmobile keel with reduced drag characteristics.
It is a further object of the present invention to improve the overall steering and propelling characteristics of a snowmobile.
A still further object of the present invention to provide a snowmobile ski keel including a wear rail having downwardly converging side faces terminating in an ice penetrating edge and a mounting bar for the wear rail having downwardly converging side faces which abut, and lie in the same planes, as, the side faces of the rail.
Snowmobiles involved in racing conventionally travel in only one direction about an endless race track. With skags or keels constructed according to the present invention the steering characteristics for turning in one direction only are enhanced. Accordingly, it is yet another object of the present invention to provide a pair of snowmobile skags or blades for use on the underside of snowmobile skiis which presents upstanding walls on the outboard side of the turn for bearing against the ice.
It is another object of the present invention to provide a snowmobile keel which is particularly adapted for snowmobile racers travelling in one direction about an endless track.
Still another object of the present invention is to provide a snowmobile ski including an underlying keel having a hardened wear rail provided with a side face which is generally vertically disposed when the ski is tilted to negotiate a turn.
Other objects and advantages of the present invention will become apparent to those ordinary skill in the art as the description thereof proceeds.